"I love to eat toothbrushes."
Translation:אני אוהב לאכול מברשות שיניים.
I know you are thinking that eating toothpaste makes more sense than eating toothbrushes, though still not recommended. DL often gives strange sentences so that we can get practice with doing whatever the lesson is about. In this case we need to know how to make the plural in a construct like toothbrush. They could have given us "I need to buy 3 new toothbrushes," but maybe goofy sentences stick better in our memory.